1. Field of the Invention
The present invention relates to a joint terminal in an electric junction box for connecting electric circuit for automobiles, and more particularly, to a joint terminal for connecting tabs of bus bars, which constitutes internal circuit, and male terminals of electric parts such as a fuse.
2. Description of the Prior Art
This type of joint terminal conventionally used is shown in FIGS. 7 and 10 (Japanese Utility Model Publication Number Showa 57-39902).
This joint terminal a has a body comprising: a fixed contact plate b; a resilient contact portion c integrally formed with the resilient contact plate b and formed by folding the fixed contact plate from one end thereof to the other end; and a pair of resilient contact arms integrally formed with the fixed contact plate b and extending from both ends thereof over the resilient contact portion c. The contact arms d oppose each other, of which end portions are bent in such a manner as to form inwardly turned half-round are portions and of which tips oppose each other over the resilient contact portion c at certain intervals.
As exemplified in FIG. 11, the joint terminal is inserted in a fixed cavity f of an electric junction box e. Then, a tab j of a bus bar i is inserted from the underside between the resilient contact portion c and the half-round are portion d' and a male terminal h of the fuse g is inserted from the upper side.
In the conventional joint terminal, as shown in FIG. 12A, the structure of the terminal is designed such that dimensional tolerance or variation in plate thickness of the male terminal h, the resilient arms d and tab j, is absorbed through the half-round are portions d', resulting in difficulty in obtaining stable contact load.
That is, the tab j is occasionally diagonally inserted as illustrated in FIG. 12B, causing deformation to the half-round are portion d'. Further, the deformation not only causes line contact between the half-round are portion d' and the tab j but also causes excessive stress over an allowable stress of the half-round are portion d' which is used as a spring, resulting in unstable electric contact. On the other hand, in order to design in such a manner that the stress of the spring is maintained within an allowable stress range, the radius of the half-round are portion d' needs to be rather large, which cannot structurally regulate the twist of the tab j at insertion.